MALAYSIAN PEAT CHARACTERISTICS

Introduction 

Of the major groups of marginal soils in Malaysia, peat is by far the most 

widespread. Malaysian peatland had been used for agriculture for a very long 

time ago. Many problems encountered by the farmers in using this land had 

been solved through intensive research carried out on peat. Government 

involvement by providing financial and technical support also has help in the 

successful of annual and industry crops cultivation on peat. Nevertheless, 

extensive exploitation of the peatland is not encouraged and where such land 

is being developed for agriculture, a high level of management is emphasized 

to minimise the occurrence of undesirable consequences which can lead to 

the drastic subsidence and rapid disappearance of the peat. 

Classification

The three major regions of Malaysia (Peninsular Malaysia, Sarawak and 

Sabah) use different systems of soil classification. The system in Peninsular 

Malaysia and Sarawak is based on the USDA Soil Taxonomy (Soil Survey 

Staff 1990) but with some criteria being modified to suit the local conditions 

while Sabah uses the FAO/UNESCO Legend (1974).

Distribution

Peat soils occur both in the highlands and lowlands, however, the highland 

organic soils are not extensive. The lowland peat occurs almost entirely in 

low-lying, poorly drained depressions or basins in the coastal areas. In 

Peninsular Malaysia, they are found in the coastal areas of the east and west 

coasts of the peninsula. Most of peat land is found in the coastal areas of 

West Johore, Kuantan and Pekan districts, the Rompin-Endau area, 

northwest Selangor and the Trans-Perak areas in the Perak Tengah and Hilir 

Perak districts. In Sarawak, peat occurs mainly between the lower stretches of 

the main river courses (basin peats) and in poorly drained interior valleys 

(valley peats). They are found in the administrative divisions of Kuching, 

Samarahan, Sri Aman, Sibu, Sarikei, Bintulu, Miri and Limbang. In Sabah, the 

organic soils are found on the coastal areas of the Klias peninsula, Krah 

swamp in Kota Belud, Sugut and Labuk estuaries and Kinabatangan 

floodplains.
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Extent

There are about 2.43 million ha of peat and organic soils in Malaysia 

accounting for about 7% of the total land area of the country. Sarawak has the 

largest area of peat in the country, covering about 1.59 million ha and 

constituting 13% of the state. This is followed by Peninsular Malaysia which 

has about 716,944 ha, comprising 5% of its total area, while Sabah has 

121,514 ha, representing 2% of the state (Figure 1 and .Table 1)

About 80 % of peat in Sarawak are deep peat. No estimates on the depths of 

peat are available for Sabah and Peninsular Malaysia. Other type soils 

associated with peat are organic clay and muck. 

Figure 1: Location of peatlands in Peninsular Malaysia, Sabah and Sarawak

Table 1: Area of peatland in Malaysia

Region Area (ha)

Peninsular Malaysia 716,944

Sabah 121,514

Sarawak 1,588,142

Total 2,426,600
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Characteristics of peat

Landscapes

The peat swamps are usually situated 2 to 4 km from the coast. In Peninsular 

Malaysia and Sabah, the general topography of the peat land tends to be flat 

whereas in Sarawak, the basin peat swamps are dome-shaped. On the west 

coast of Peninsular Malaysia, the peat swamps are formed in depressions

consisting predominantly of marine clay deposits which are either sulfidic in 

nature, or consist of an admixture of marine and riverine deposits especially in 

areas along river courses. On the east coast of the peninsula, particularly in 

the states of Kelantan and Terengganu, peat swamps are found between the 

young and old BRIS (Beach Ridges Interspersed with Swales) landscapes. In 

Pahang and eastern Johore, the peat swamps are situated immediately 

adjacent to the BRIS landscape, approximately 5 to 10 km from the presentday coastline. 

In Sarawak, the coastal and deltaic peat swamps have convex surfaces with 

the convexity of the swamp surfaces becoming more pronounced with 

distance from the sea. Maximum heights recorded in the Daro Forest Reserve 

and Loba Kabang Protected Forest were 4 m. The swamp surface is like that 

of an inverted saucer with almost flat bog plain at the centre.

Morphological characteristics

Morphologically, the lowland peat in the three regions is quite similar. In the 

natural state, the lowland virgin peat consists of dark reddish brown to black, 

loose, partly decomposed leaves, branches, twigs and tree trunks with a low 

mineral content. The water table is always high and occurs at or near the 

surface. In drained areas, the peat is transformed to a compact mass 

consisting of partially and well-decomposed plant remains with large wood 

fragments and tree trunks embedded in it, as a result of decomposition, 

shrinkage and consolidation of the virgin peat. 

In the west coast peat of Peninsular Malaysia and most of the peat in 

Sarawak, the underlying materials consist of sulfidic marine clay, while in the 

east coast of the peninsula, the peat is underlain by riverine alluvium, 

colluvium and sand. 

The common soil profile morphology in the drained peat consists of three 

distinct layers; an upper layer of 20-30 cm thick consisting of welldecomposed organic materials of the sapric type, a middle layer of 30-40 cm 

thick containing semi-decomposed organic materials belonging to the hemic 

type and a lower layer of fibric peat which is made up of a large quantity of 
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relatively undecomposed organic materials consisting of tree trunks, large 

wood fragments and branches. The fibric materials are often submerged in 

water at a depth of 60-70 cm. The rubbed colours of these layers vary from 

very dusky red (2.5 YR 3/2) to very dark yellowish brown (5YR 3/2) depending 

on the stage of decomposition. In general, the thickness of the deep peat in 

Malaysia exceeds 5 m, although in Sarawak peat thickness exceeding 15 m 

has been recorded.

Physical characteristics

Field moisture content of the peat ranges from about 100 to 1300 %, on a dry 

weight basis. The high water content results in high buoyancy and high pore 

volume leading to low bulk density and low bearing capacity. 

The ash content in most of the peat of the west coast of Peninsular Malaysia 

and in Sarawak is less than 10%, showing a very high content of organic 

matter. This is indicated by a loss of ignition value exceeding 90%. In the east 

coast of the peninsula, the organic matter content is highly variable as the 

mineral content ranges from 10% to as high as 65%. This variability is due to 

periodic disposition of mineral sediments by seasonal floods. 

The bulk density for the top 30 cm of the peat is low and varies from 0.1 to 0.2 

g per cubic centimeters in peat of Peninsular Malaysia and Sarawak. 

Upon drainage and cultivation, peat decomposes and shrinks, resulting in 

subsidence and lowering of the ground surface. In the first 2 years of draining 

the peat in the West Johore Integrated Project, the rate of subsidence is 

drastic and reaches a value of 50 cm. The sudden drop in the peat level is 

due to the collapse of the loose fibric materials followed by decomposition and 

compaction of resultant hemic and sapric materials. In subsequent years, as a 

result of the consolidation of the sapric and hemic materials, the rate of 

subsidence is only 2 to 3 cm per annum. In Sarawak, a subsidence rate of 6 

cm per annum has been reported for peat with a water table at 75-100 cm.

Chemical characteristics

Organic soils in the three regions are very acidic with very low pH values 

ranging from 3.0 to 4.5. In some cases where sulphidic materials are found 

within the profile, pH values can drop below 3.0. 

The electrical conductivity values are generally low (less than 1 dS/m). 

However, in some coastal areas which are influenced by sea water, e.g. 

Tanjung Karang, values of up to 4.7 dS/m have been recorded. 
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The organic carbon values are in the region of 30 to 40%. However, due to its 

high C/N ratio, very little nitrogen is mineralised unless large quantities of 

nitrogenous fertilizers are applied. 

Peat has high CEC values ranging from 40 cmol (+) per kg soil in the east 

coast of Peninsular Malaysia to 40 to 80 cmol (+) per kg soil in west Johore 

and 145 cmol (+) per kg soil in Jalan Kebun in Selangor. In Sarawak, values 

of 40 to 135 cmol (+) per kg soil have been reported. Variability in the CEC 

values of peat is due to the stage of decomposition and nature of the organic 

matter. 

Peat soils have low exchangeable bases and base saturation values. Micronutrients, particularly Cu, Bo and Zn, are also deficient. Iron is found to be 

high. Severe Cu deficiencies of maize, cassava and oil palm on peat have

been observed.

The acid and hyper acid conditions of the peat are readily neutralised by 

liming and the use of oil palm bunch ash. The problems associated with 

micronutrient deficiencies are no longer serious threats to crop production as 

these have been overcome by intensive research.

Profile characteristics

Based on field investigations carried out in Johore and Selangor, most of the 

cultivated peat had the sapric-hemic-fibric profile morphology. This profile 

morphology was developed when the peat is drained and this encouraged

decomposition of the peat. Peat decomposition enhanced consolidation and 

compaction of the broken down organic materials resulting in the formation of 

the sapric and hemic layers. This process invariably leads to the subsidence 

of the ground surface. Generally, in draining the peat swamp, emphasis is 

focussed on controlled drainage which involves a gradual lowering of the 

ground water table to favour the formation of the sapric and hemic layers 

while ensuring that the subsidence is kept to a minimum.

Conclusion

While peat soils are not comparable to mineral soils for crop production, they 

are highly suitable for a wide range of crops especially those with shallow

rooting and fibrous root systems including oil palm, pineapples, vegetables, 

cassava, Liberica coffee, mulberry, banana, sago etc. In Sarawak, relatively 

large areas of the peat swamps are bearing species of valuable timber such 

as the "Ramin" (Contystylus bancanus).
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(Extracted from the Proceedings of the International Symposium on Tropical 

Peatland, 6-10 May 1991, in Kuching, Sarawak and Progress Report of Oil 

Palm Inventory, Joint Committee on Carbon Emission Dec. 2010)